Our goal is to develop a novel animal model for autoimmune hepatitis (AIH). AIM is a severe adverse immune reaction afflicting the liver, resulting in the progressive destruction of the parenchyma. To date no valid animal model is available that reflects the clinical and pathological features of human AIH and allows to study its etiology and immunopathology. A hallmark of AIH is the presence of liver/kidney microsomal antibodies that recognize the cytochrome P450 isoform 2D6 (CYP2D6) as a major target autoantigen. Thus, it is the objective to break tolerance to a transgenically expressed target antigen (human CYP2D6) in the target organ (liver) of CYP2D6-mice by infection of a liver-tropic virus (adenovirus), ensuring local inflammation and delivery of large quantities of the triggering antigen (human CYP2D6). From preliminary experiments we know that this approach results in persistent liver damage in CYP2D6-mice, which is characterized by lymphocyte infiltration, hepatic fibrosis, and high titer anti-CYP2D6 antibodies. In addition to its obvious benefit as a novel model to study AIH, the CYP2D6 mouse may also be used as a proof of principle for studying general mechanisms involved in fibrinogenesis and in drug-induced autoimmune diseases that are mediated by members of the cytochrome P450 family, such as Halothane hepatitis (CYP2E1) or procainamide-induced lupus (CYP2D6). [unreadable] [unreadable] Aim 1: Development and characterization of the CYP2D6-mouse model for autoimmune hepatitis Aim 2: Mechansims of autoimmune liver damage in the CYP2D-mouse model; Aim 3: Evaluation of possible treatments to abrogate autoimmunity in the CYP2D6-mouse model. [unreadable] [unreadable]